It used to be that when you went to upload a data file there would be a link to documentation (see attached screenshot).
The user guide link used to take you to documentation about how to upload data (something I routinely need to look up): https://docs.google.com/document/d/1X7q4zYAb16Py8raxGhP_HPzp5KRjrNfTeSR0wIRrzQU/edit#heading=h.qbamm880nf6g
Now it takes you to a general documentation page: https://software.broadinstitute.org/firecloud/documentation/
Which while helpful, is less relevant to the specifics of uploading data.
(Note that this post is a duplicate of one in FirecloudDocumentation, but since I think that was the wrong category I am reopening it here.)